#define LED 12
int LED_TTL = HIGH;
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED, OUTPUT);
  pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED, LED_TTL);
  digitalWrite(13, 1-LED_TTL);
  delay(200);
  LED_TTL = !LED_TTL;
}

